This invention relates to a fractionation process. In another aspect, it relates to a fractionation process in which two fractionators and a common accumulator are used. In another aspect, it relates to such a fractionation process in which the overhead of one fractionator is used as the feed for the second and the bottoms product of the second fractionator is used as reflux for the first fractionator. In yet another aspect, this invention relates to a fractionation process in which a single vessel divided by a baffle is used to accumulate and distribute the reflux for the first fractionation and the feed charge for the second fractionator. In yet another aspect, this invention relates to a fractionation process used to separate alcohol from an alcohol-containing mixture. In yet another aspect, this invention relates to such a fractionation process for the separation of an amine-methanol mixture.
This invention also relates to the apparatus of a fractionation process. More specifically, this invention relates to a combined reflux accumulator and feed surge vessel in combination with two fractionators.
In a chemical process a tank or section with a fractionation column is often used for accumulating condensed vapor from a fractionation operation. These vessels are usually denominated as accumulators and are generally used when at least part of the accumulated condensate will be used as reflux in the fractionation operation. The material stored in the accumulator assures a ready supply of reflux for the distillation.
However, the condensed vapor from the fractionation operation can have valuable constituents in it which may be reused thereby making it desirable to obtain the constituents before using the condensed vapors as reflux. By removing the valuable constituent before the condensed vapor mixture is used as reflux reduces the amount of the valuable constituent that is distilled as overhead in the fractionator and leads to a more efficient and economical process.
The processing of raw natural gas is a good example of a process in which such a procedure would be advantageous. In the processing of raw natural gas it is common practice to provide means for preventing hydrate formation. If the gas is sour, that is, it contains acid gases such as hydrogen sulfide, carbon dioxide, and the like, it is also common practice to remove these components from the gas or the liquid products recovered from it prior to further processing or use. Therefore, where a sour gas has been treated by methanol injection to inhibit hydration formation and is further treated in an acid gas absorber for removal of acidic components such as CO.sub.2, H.sub.2 S, and COS, and the like, rich solvent from the absorber contains the absorber solvent, acid gases, methanol, and water. It is generally economical to recover the methanol for reuse, therefore, when the rich solvent from the absorber is fractionated, and an overhead of methanol, water, and acid gases is obtained, it would be beneficial to subject the condensed methanol-water vapors to second fractionation to recover high purity methanol for reuse instead of using the condensed methanol-water vapors merely for reflux.
An object of the present invention, therefore, is to provide an efficient and economical fractionation process for separating a valuable constituent from a mixture.
More specifically, it is an object of this invention to provide an efficient and economical fractionation process for an amine-alcohol separation.
Another object of the present invention is to provide a fractionation process for separating a valuable constituent from a mixture that minimizes the vessels required for the process.
Another object of the present invention is to provide a fractionation process for separating a valuable constituent from a mixture that also minimizes the instrumentations to control the process.
Yet another object of the invention is to provide the apparatus for a fractionation process that is efficient, economical, and minimizes the vessels required as well as the instrumentations to control the process.
Still another object of the present invention is to provide an apparatus for an amine-alcohol separation process that is efficient, economical and minimizes the vessels required as well as the instrumentations to control the process.
Other objects, aspects, and the advantages of this invention will be readily apparent to those skilled in the art upon a study of this disclosure and the appended claims.